1. Field of the Invention
The present invention relates to apparatuses for determining motor overheating, methods for determining motor overheating, computer-readable media, motor control apparatuses, motor control methods, and printing apparatuses.
2. Description of the Related Art
Various types of motors are installed in printing apparatuses such as inkjet printers, including carry motors for carrying media such as paper to be printed and motors for moving printing sections which are for printing on media such as paper. When these motors are driven continuously, they may sometimes rise in temperature due to generation of heat and go into a high temperature condition. Since there is a risk of faults such as coil burnout when the motor is in a high temperature condition, printing apparatuses are provided with monitoring devices to ensure that the motor does not go into a high temperature condition.
One such monitoring device (see JP 2002-186285A) is a device that monitors the motor temperature based on the amount of drive of the motor. This device successively adds the amount of drive of the motor and examines whether or not the motor is in a high temperature condition by checking whether or not the integrated value has reached a predetermined value. In other words, the temperature of the motor is inferred from the amount of drive of the motor by focusing on the relationship between the amount of drive of the motor and the heat produced by the motor. A determination is made that the motor is in a high temperature condition when the integrated value of the amount of drive of the motor reaches the predetermined value, and a transition is made to heat restriction control to restrict motor heating by suppressing motor drive. By transitioning to this control, driving of the motor is continued while preventing the temperature of the motor from rising further. It should be noted that it is proposed that when the motor has not been driven for a short while, the integrated value of the amount of drive of the motor should be gradually reduced, and when the motor has not been driven for a long time, the integrated value of the amount of drive of the motor should be reset to zero.
By monitoring the motor temperature condition based on the amount of drive of the motor, it is possible to obviate various sensors such as temperature sensors so that it is possible to achieve monitoring without increasing the number of components and without incurring much cost.
However, devices that monitor motor temperature conditions based on the amount of drive of the motor have the following problems. That is, the integrated value is reduced corresponding to the motor temperature condition by, for example, gradually reducing the amount of drive of the motor when the motor has not been driven for a short while, or by resetting the integrated value of the amount of drive of the motor to zero when the motor has not been driven for a long time. However, there has been no measure in place for when the motor is stopped for an extremely short time, for example, when the drive of the motor is stopped for an extremely short period of around one second, such as several tens to several hundreds of milliseconds. For this reason, sometimes the motor is judged to be in a high temperature condition and heat restriction control is activated despite the motor not being in a high temperature condition. This has sometimes caused problems of extra time being required for printing and printing speeds being reduced.